Use of Anatomical Landmark in Locate Occlusal Plane.

The plane of occlusion refers to an imaginary surface that theoretically touches incisal edges of the incisors and the tips of the occluding surfaces of the posterior teeth". A plane usually signifies a flat surface; however, it is not so where the occlusal plane is concerned. Two areas comprising of anterior and posterior teeth constitute the occlusal plane and must be considered individually. Anterior tooth position is governed by esthetics, phonetics and the required anterior guidance. On the contrary, functional needs predominantly determine the position of posterior teeth and this position is also affected by the incorporation of the anteroposterior and mediolateral curves. Optimal function, aesthetics and phonetics following prosthodontic rehabilitation is dependent on the establishment of physiologically accurate vertical dimensions of occlusion, palatal contours, positioning of the teeth and the level of occlusal plane.

The occlusal plane orientation is lost in patients with mutilated dentitions or those rendered edentulous and needs to be re-established for optimal function and comfort.

Different intra- and extra-oral landmarks used by clinicians to define the level of the occlusal plane include the upper lip, corners of mouth, lateral margins of tongue, Camper's plane and interpupillary line, the parotid papilla and the retromolar pad (RMP).

Any discrepancy in establishing the optimal level of occlusal plane causes adverse effects on periodontal tissues in dentate individuals and may result in vague symptoms such as headaches, migraines or stiffened shoulders and in edentulous patients, compromising the stability of the prosthesis, ultimately leading to alveolar bone resorption.

A combination of various landmark along with a judicious clinical judgment should be taken into account for the location of the occlusal plane in edentulous patients.

If the level of occlusal plane is too high, the tongue is unable to lie on the lingual cusps of the mandibular denture teeth and hence, fails to counter the movement of the denture. It may also result in food accretion in the labial and lingual sulci. In contrast, a low level of occlusal plane will promote tongue and cheek biting. Therefore, it is mandatory for the prosthodontist to re-establish the lost occlusal plane, both while dealing with multiple long span posterior restorations as well as in complete denture prosthodontics.

Material and Methods:

Forty dentulous patients. The mandibular posterior occlusal plane was determined on the level of coronoid notch (CN) on the anterior part of ramus. Then We will measure the occlusal plane in all forty a participants determined to the level of CN at the anterior border of ramus in mandible.

Inclusion :

• Stable systemic health, including absence of a history of cardiovascular disease
• No evidence of infection or trauma in oral region
• Negative history of TMJ disorders
• All subjects had natural maxillary and mandibular teeth.
• All subjects exhibited Class I skeletal and dental relationships with no prosthetic dental replacement.

Exclusion criteria

Subjects with Claa II or Class III relationships,fractured or abraded edges of the teeth,ankyloglossia and orthodontic treatment The mandibular posterior occlusal plane was determined according to the level of coronoid notch{CN} (greatest concavity anterior border of the ramus) by measure the distance between the occlusal plane a with ages beyond the accepted age range

Inclusion :

• Stable systemic health, including absence of a history of cardiovascular disease
• No evidence of infection or trauma in oral region
• Negative history of TMJ disorders
• All subjects had natural maxillary and mandibular All subjects exhibited Class I skeletal and dental relationships with no prosthetic dental replacement.

Exclusion criteria

Subjects with Claa II or Class III relationships,fractured or abraded edges of the teeth,ankyloglossia and orthodontic treatment were excluded from the study.